Choose between 7 
and 14 pieces 
to fill the outline.
To flip a piece, click on it, and press the flip button: 
To rotate a piece, hover above a vertex until the rotate indicator appears. Click, hold, and rotate the piece to the desired orientation.
To receive help, click on the question mark; outlines will briefly appear to guide you.
You can display or hide the timer by clicking on the clock.
To reset the work space, click on 
.
For finishing touches, choose a color from the palate and click on a piece. 
To create a custom outline, move the pieces to the desired positions. Then, choose an empty box, and click "Save."
To use the custom outline, choose the puzzle piece, and the tangrams will reset themselves.